Pressure vessel with high-pressure window

The present invention relates to a pressure vessel (1) having a pressure vessel wall (1a) which completely surrounds a reaction chamber (2) as a pressure space for the initiation and/or promotion of chemical and/or physical pressure reactions of a sample (P) to be heated which is accommodated in the reaction chamber (2), wherein the pressure vessel wall (1a) has an infrared-permeable high-pressure window (30) which extends away outward in a direction from the reaction chamber (2) and which is supported in the pressure vessel wall (1a) with respect to a pressure in the reaction chamber (2), wherein the pressure vessel (1) furthermore has an infrared to temperature sensor (40) which is situated directly opposite the high-pressure window (30), in order to measure the temperature of a sample (P), accommodated in the reaction chamber (2), during a pressure reaction through the high-pressure window (30).